Magnetic tape cartridge having a latch spring with one of an inclined guide surface and a bent portion supported by a support member

ABSTRACT

A single-reel magnetic tape cartridge has a cartridge casing and a single reel around which a magnetic tape is wound and which is contained in the cartridge casing for rotation, in which the magnetic tape is fixed at the leading edge thereof to a leader pin employed for extracting the magnetic tape from the cartridge and the flanges at the upper and lower ends of the leader pin are engaged by the lateral drawing force of a latch spring removably held in the tape cartridge casing. Even for cases in which there is a deviation in the insertion position in which leader pin is inserted by the record and playback apparatus, etc. causing the entry path of the leader pin into the cartridge casing to be off track, etc., it is still possible for the leader pin to be inserted into the cartridge casing. The incline angle, in relation to the insertion direction of the leader pin, at the point at which the flanges of the leader pin are brought into abutment with the guide surface of the latch spring is set within the range of 30°±5°.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention related to a magnetic tape cartridge, and inparticular to a magnetic tape cartridge and a single reel around which amagnetic tape with a leader pin fixed to the leading end thereof iswound and which is contained in the cartridge casing for rotation,having a latch spring removably mounted at the cartridge casing tapeoutlet opening, and the cartridge case opening is provided with anopening and closing slide door and lock.

2. Description of the Related Art

There has been known a single-reel magnetic tape cartridge as forexample the type disclosed in Japanese Unexamined Patent Publication No.11(1999)-242870, comprising a cartridge casing and a single reel aroundwhich a magnetic tape is wound and which is contained in the cartridgecasing for rotation, as a recording medium for an external storagedevice for a computer and the like. In this type of magnetic tapecartridge, a leader pin fixed to the lead end of the magnetic tape isengaged by the lateral drawing force of a latch spring fixed in the tapecartridge casing, and is removably held in the cartridge casing.

FIGS. 23 and 24 show a vertical cross-section view and a fragmentaryhorizontal cross-sectional view, respectively of the structure of thepin holding portion contained in aforementioned publication.

In FIGS. 23 and 24, synthetic resin cartridge casing 4 is formed byupper half 2 and lower half 3, and a single reel (not shown) aroundwhich the magnetic tape, connected at the tail end thereof to leader pin5, is wound. A tape outlet opening 8 for drawing out the magnetic tapeis formed on one sidewall of cartridge casing 4, and tape outlet opening8 is provided with a slide door 20, which is movable in the directionparallel with the side of cartridge casing 4. Slide door 20 is proppedin the direction of the closed position of tape outlet opening 8 by adoor spring (not shown).

A concave recess 9 for extracting leader pin 5 is formed adjacent totape outlet opening 8 of cartridge casing 4, and a latch spring 30 isprovided for removably holding leader pin 5 in recess 9 when themagnetic tape cartridge is not in use and the tape is in the completelywound state.

When the magnetic tape cartridge is installed in the record and playbackapparatus of an external storage device slide door 20 opens, leader pin5 is drawn out by a robot arm of the record and playback apparatus, andthe magnetic tape is drawn out to the predetermined running positionfrom which reading and writing data thereto are possible.

Leader pin 5, as shown clearly in FIG. 23, comprises a shaft-shaped tapeclamp 5 a at the center thereof, around which the lead end of themagnetic tape is wound and secured in place by fastening across-sectional C clamp 5 e. Tape clamp 5 a is connected at its upperand lower ends to a pair of thin plate-shaped flanges 5 d, and on theoutside of flanges 5 d in the axial direction are a pair of smalldiameter portions 5 b, which are caught by the robot arm of the playbackand record system, which are spaced by a pair of column-shaped flanges 5c.

Latch spring 30, as in the form shown in FIG. 25 for example, is formedof a plate spring pinched between respective upper and lower halves 2and 3 of cartridge casing 4, and upper and lower flanges 5 c of leaderpin 5 are each inserted into respective recesses 9 on the upper andlower halves of cartridge casing 4 and removably held therein by latchspring 30.

As shown in FIG. 25, latch spring 30 is formed in a substantially Ushape in plan and is symmetrical about the horizontal axis thereof, andcomprises a vertical base portion 30 a from the upper and lower ends ofwhich extends a back plate 30 c and a pair of arms 30 b that extendsubstantially parallel to each other, on the free end portion of eacharm 30 b is provided a pin holding portion 30 d. The area between upperand lower arms 30 b is cut out, and arms 30 b are formed so that onlypin holding portion 30 d is brought into abutment with flange 5 c ofleader pin 5. Each pin holding portion 30 d protrudes in a mound-shape,and a rear inclined pin guide surface 31 is formed at the lead endthereof (FIG. 24). When leader pin 5 is held by the robot arm insertedinto cartridge casing 4, at the first contact made with guide surface 31by the outer circumference of flange 5 c of leader pin 5, arm 30 b oflatch spring 30 presses against flange 5 c and is resiliently deflectedtoward the side, and it is possible for leader pin to be inserted in torecess 9. Having passed guide surface 31, flange 5 c of leader pin 5, asshown in FIG. 24, is held against the inner wall of recess 9 by theresilient force of pin holding portion 30 d, and with this type of latchpin, with the fastening of respective upper and lower halves 2 and 3 ofcartridge casing 4, the upper and lower edges of base portion 30 a andback wall 30 c are pinched and fixed in place by respective upper andlower halves 2 and 3.

FIG. 26 provides detailed illustration of the state in which leader pin5 is inserted from tape outlet opening 8 into cartridge casing 4.

Recess 9, which accommodates leader pin 5, is provided withstraight-line shaped guide walls 9A and 9B, for guiding flange 5 c ofleader pin 5 into the back of recess 9, and a semi-spherical holdingwall 9 c, which is of a slightly larger diameter than that of flange 5c.

Up until now, leader pin 5 has been designed so that the center axis Sthereof passes through the center of the curvature of semi-sphericalholding wall 9 c in the back of recess 9 along a perpendicular centerline L1 of the sidewall of tape outlet opening 8 of cartridge casing 4and is inserted into the recess 9, and if flange 5 c of leader pin 5 isbrought into abutment with leader pin guide surface 31 of the free endof latch spring 31, flange 5 c is drawn in, and by the pressure broughtto bear against guide surface 31, arm 30 b is deflected toward the side(left side of the Figure) whereby it becomes possible for leader pin 5to be inserted into the back of recess 9, and flange 5 c, which has beenpassed over guide surface 31 to the back of recess 9, is held by theresilient force of pin holding portion 30 d of latch spring 30 in theholding wall of recess 9.

However, because there are instances in which, due to unevenness, etc.in the relative positions of the robot arm of the record and playbackapparatus and the magnetic tape cartridge inserted therein, leader pin 5is inserted into recess 9 in a state in which the center axis S thereofis off track to the left or right of center line L1 of recess 9, ifrecess 9 is widened on the tape outlet opening 8 side to and guide walls9A and 9B are provided inclining surfaces opening toward the outwarddirection, even if leader pin 5 is inserted into recess 9 in a state inwhich the center axis S thereof is off-center with respect to centerline L1, guide walls 9A and 9B are structured so as to guide flange 5 cso that center axis S is directed toward the center of the curvature ofholding wall 9 c.

However, because there is also unevenness in the relative positions ofguide surface 31 of latch spring 30, as shown in FIG. 26, when insertedinto recess 9 from the state in which flange 5 c of leader pin 5 isguided on guide wall 9A on the latch spring 30 side, if guide surface 31is only pressed against by flange 5 c, because arm 30 b of latch spring30 will not be deflected toward the side, and a problem arises in thatit is not possible for leader pin 5 to be inserted into cartridge casing4.

Guide surface 31 of latch spring 30 has a predetermined angle α′relative to parallel straight line L2 parallel to center line L1.Conventionally, α′ has been an angle of 55°. Note that because the anglebetween guide wall 9 a of recess 9 on the latch spring 30 side andaforementioned straight line L2 is 10°, angle β′ between guide surface31 and guide wall 9 a on the latch spring 30 side is 45°.

Because of this, when flange 5 c is in the state of being guided byguide wall 9A, there are cases in which when flange 5 c is inserted intorecess 9, a problem occurs in that arm 30 b of latch spring 30 is notdeflected to the side even if guide surface 31 is pressed against byflange 5 c of leader pin 5.

On the one hand, there are a variety of latch springs available for usein holding leader pin 5 in recess 9 beside that of the form describedabove. However, when a latch spring is fitted to cartridge casing 4,depending on the type and attachment structure thereof, there is adifference in the amount of the leader pin holding portion at the leadedge of the latch spring that projects toward recess 9, and depending onthe pin holding portion, the engaging strength thereof changes, andproblems relating to instability in inserting and removing the pinarise.

In particular, when the latch spring fitted to upper half 3 and thelatch spring fitted are separate parts, this is a cause of difference inthe upper and lower engaging strength, and there is fear that leader pin5 will tilt. In addition, if the amount of the pin holding portion ofthe latch spring that projects is small, the holding strength isweakened, and there is a chance that vibrations, etc. caused whenmagnetic cartridges are stored or shipped can cause leader pin 5 to bedislodged from recess 9, and conversely, if the amount of the pinholding portion that projects is large, there is a chance that the formof the latch spring will become deformed when magnetic tape cartridgesare stored or shipped; in either case, faulty insertion and removal ofleader pin 5 caused thereby give rise to the fear of diminishedoperational reliability.

FIG. 27 shows a possible type of construction of separate upper andlower latch springs. Latch spring 55 is formed of separate upper andlower wire spring members, provided with a pin holding portion 5 a onthe free end of each thereof that contacts leader pin 5, arms 55 bextending from pin holding portions 55 a in the direction opposite thetape outlet opening, and a base portion bent into a substantiallyL-shape and inserted into and fixed in a curved groove 56 a of fixingportion 56 formed on the rear end portion of recess 25 on an inner wallof the cartridge casing, by which latch spring 55 is held in apredetermined position.

However, if the fixed position of latch spring 55 is supported only atthe rear end position of arms 55 b, which are the farthest removed fromposition at which leader pin is contacted, a microscopic displacement offitting portion 55 e of aforementioned fixing portion 55 has an effecton pin holding portion 55 a, and the amount thereof that projects towardrecess 9 of leader pin 5 changes, causing aforementioned weakening ofengaging strength and instability in inserting and removing leader pin5. Further, even if the fitting portion of the rear end of the armportion of latch spring 55 is of a construction in which it is fixed toa projecting heat fused fixing portion, a displacement of the fittingportion of the fixing portion will cause the same change to the engagingpower.

Also, in a magnetic cartridge of the type described above, if tapeoutlet opening 8 for extracting the magnetic tape is jarred open by ashock caused during shipping or storage thereof, or any other time it isnot being used, because it is possible that foreign matter beinadvertently introduced to the inside of the cartridge casing, morethan simply propping the slide door in the direction of the closedposition by use of a door spring, but locking the slide dooradvantageously prevents inadvertent opening of the slide door andimproves reliability.

SUMMARY OF THE INVENTION

In view of the circumstances described above, the first objective of thepresent invention is to provide a latch spring configuration assuringreliable, consistent, smooth insertion of the lead pin into thecartridge casing, regardless of unevenness based on deviation of theposition in which the leader pin is inserted by the member of the recordand playback apparatus, or inaccurate disposition of the guide surfaceof the latch spring.

The second object of the present invention is to provide a magnetic tapecartridge casing having a latch spring that assures for the accuracy ofthe position in which the lead pin is held is and stabilizes theengaging power to carry out accurate loading and retracting of themagnetic tape.

The third objective of the present invention is to provide a magnetictape cartridge in which locking of the slide door in the closed stateimproves reliable operability thereof.

A magnetic tape cartridge of the first invention of the presentapplication comprising a single reel around which a magnetic tape iswound, contained in a cartridge casing for rotation, the magnetic tapebeing attached at the lead end thereof to a leader pin for extractingthe magnetic tape from the cartridge, the leader pin being removablyheld inside the cartridge casing at the both ends thereof by the lateralresilient force of a latch spring provided in the cartridge casing, thelatch spring being provided with a guide surface that guides the leaderpin when it is inserted into the cartridge casing and a holding portionthat holds the leader pin within the case after it has passed the guidesurface, wherein the diagonal angle of the guide surface at the point ofcontact with the leader pin with respect to the direction in which theleader pin is inserted is formed so that by only being pushed against bythe leader pin, regardless of which of several positions from which theleader spring is inserted into the cartridge casing, is set so that thelatch spring is deflected to the side.

More specifically, the angle at the point of contact with the leaderpin, with respect to the direction from which the leader pin isinserted, is set within the range of 30°±5°.

In addition, in a magnetic tape cartridge of the second invention of thepresent application comprises a single reel around which a magnetic tapeis wound, contained in a cartridge casing for rotation, the magnetictape being attached at the lead end thereof to a leader pin forextracting the magnetic tape from the cartridge, the leader pin beingremovably held inside the cartridge casing at the both ends thereof inby the lateral resilient force of a latch spring provided in thecartridge casing, wherein in at least one place between the point atwhich the lead end comes in contact with the leader pin and the fixingportion fixed within the cartridge casing, a bent portion is provided,and between aforementioned holding portion supported by the supportingmember of the bent portion and the bent portion a resilientlytransformable arm portion is formed, and when the distance between thesupporting member and the leader pin is designated as L, a distance Sbetween the supporting member and the fixing portion, a relationship ofS≧(⅓) L is sufficient. The angle of bend in aforementioned bent portioncan be substantially 180° or 90°.

Also, in a magnetic tape cartridge of the third invention of the presentapplication comprising a single reel around which a magnetic tape iswound, contained in a cartridge casing for rotation, provided with atape outlet opening for extracting the magnetic tape from the cartridgecasing and an opening and closing slide door, the slide door is providedwith an opener portion that is brought into abutment with the dooroperating member of the record and playback apparatus and causes theslide door to move in the direction of the open position, and a lockportion that engages an engaging portion of the cartridge casing to lockthe slide door in the locked position and connects with the dooroperating member of the record and playback apparatus, which disengagesand unlocks the locking member from the engaging portion.

More specifically, the lock portion is provided at the upper and lowerportions of the lead end of the slide door, and the of the contactsurface of the opener portion that is brought into abutment withaforementioned door operating member can be formed as a slanted surfacethat connects with the door operating member and causes the lead end ofslide door to move toward the opening position.

In addition, the lock portion can be provided in the opener portion ofthe slide door, and the opener portion can be formed so that whenconnected with the door operating member, the opener portion is moved ortransformed in the direction in which the engaging portion and lockportion are disengaged and unlocked direction. In this case, a groove isformed above and below the opener portion, and it is preferable that theopener portion easily transforms into the unlock direction.

Also, the slide door can be of a type provided with a lock portionformed on a movable locking member so that the slide door slides intothe open position, an unlocking member that moves the locking member tothe locked position, wherein the slide door is propped by the resilientforce of a spring into the closed position.

In this case, it is preferable that the unlocking member of the openerportion of the slide door faces the contacting portion of thedoor-operating member. Further, it is preferable to provide the slidedoor so that it is possible for the locking member to move in asubstantially perpendicular direction to the opening and closingdirection thereof.

Still further, in a magnetic tape cartridge of the fourth invention ofthe present application comprises a single reel around which a magnetictape is wound, contained in a cartridge casing for rotation, providedwith a tape outlet opening for extracting the magnetic tape from thecartridge casing and an opening and closing slide door, the slide doorcomprises an opener portion moved by the door operating member of therecord and playback apparatus toward the direction of the open position,and a through-hole that serves as an engaging hole formed in a wall ofthe cartridge casing through which a projecting-type locking memberprovided with a warped portion is inserted and engaged from inside thecartridge casing to lock the slide door in the closed state, wherein anunlocking member inserted into the engaging hole from outside thecartridge casing transforms aforementioned warped portion through theprojecting-type locking member, whereby the projecting-type lockingmember is moved to the unlocked position. In this case, the engaginghole is formed in the upper or lower wall of the cartridge casing and itis preferable that it be possible for the warped portion to move in adirection substantially perpendicular to that of the opening and closingof the slide door.

According to the first invention of the present application, byproviding the guide surface of the latch spring with a diagonal angle atthe point of contact with the leader pin so that by only being pushedagainst by the leader pin, regardless of which of several positions fromwhich the leader spring is inserted into the cartridge casing, the latchspring is deflected to the side, even if there is inconsistency inrelation to the path by which the leader pin enters the cartridgecasing, and the leader pin can be emplaced in the cartridge housing inthe predetermined position without impediment.

According to the second invention of the present application, the latchspring is provided with a bent portion in at least one place between thepin holding portion at the lead end thereof and the fixing portion fixedwithin the cartridge casing, said bent portion being supported by asupporting member so that the arm portion is provided so as to beresiliently transformable, and by providing distance S between thesupporting member and the fixing portion greater than ⅓ of distance L,which is the distance between the supporting member and the leader pinholding portion, accuracy of the fitting position is improved, theamount of the leader pin holding portion that projects toward theemplacement portion is stabilized, insertion into and removal of theleader pin from the emplacement portion can be performed with accuracy,and reliable loading operability is assured.

According to the third and fourth inventions of the present applicationthe by providing the tape outlet opening for extracting the magnetictape a lock mechanism that locks the opening and closing slide door inthe locked state thereof, even if tape outlet opening 8 for extractingthe magnetic tape is jarred open by a shock, etc. caused during shippingor storage thereof, or any other time it is not being used, the slidedoor is maintained in the locked state and the entry of foreign matterinto the inside of the cartridge casing is prevented, and reliability isimproved.

In particular, for cases in which the engagement of the lock portion andthe engaging portion is configured so as to be unlocked when the openerportion of the font end of the slide door is connected to the dooroperating member, it is advantageous that a specialized unlocking memberdoes not have to be supplied separately.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a magnetic tape cartridge implementingthe present invention, with the magnetic tape in the extracted state,

FIG. 2 illustrates the magnetic tape cartridge of the first invention ofthe present application, in the state in which the flange of the leaderpin is brought into abutment with the guide surface of the latch springwhen the leader pin is inserted into the cartridge casing,

FIG. 3 illustrates the state of the embodiment of FIG. 2 in which theflange of the leader pin passes over the latch spring holding portion,

FIG. 4 illustrates the state of the embodiment of FIG. 2 in which theflange of the leader pin is held in the back of the recess of thecartridge casing,

FIG. 5 is a front view of the vicinity to the side of the tape outletopening of an embodiment of the magnetic tape cartridge of the secondinvention of the present application, in which the slide door is open,

FIG. 6 shows the same view as FIG. 5, with the top half of the cartridgecasing removed,

FIGS. 7A and 7B show the fixing portion of FIG. 6 before and after ithas been heat fused,

FIG. 8 is a plan view of the main part of the magnetic cartridge ofanother embodiment, with the upper half of the casing thereof removed,

FIGS. 9A and 9B are cross-sectional views of the fixing portion of FIG.8 before and after it has been heat fused,

FIG. 10 is a plan view of the main part of an embodiment of a magnetictape cartridge of the present invention having a different type of latchspring,

FIG. 11 is a plan view of the main part of an embodiment of a magnetictape cartridge of the present invention having yet another differenttype of latch spring, with the upper half of the cartridge casingremoved,

FIG. 12 is a perspective view of the vicinity to the side of the tapeoutlet opening of the magnetic tape cartridge according to the thirdinvention of the present application, in the state in which the slidedoor is closed,

FIG. 13 is a front cross-sectional view of the vicinity to the side ofthe tape outlet opening of FIG. 12 with the slide door in the lockedstate,

FIG. 14 is front cross-sectional view of the vicinity to the side of thetape outlet opening of FIG. 13 in the unlocked state,

FIG. 15 is a cross-sectional plan view of the slide door of anotherembodiment in the locked state,

FIG. 16 is the same cross-sectional plan view of FIG. 15 in the unlockedstate,

FIG. 17 is a perspective view of the lead end of the slide door of FIG.15,

FIG. 18 is rear cross-sectional view of yet another embodiment of theslide door, in the locked state,

FIG. 19 is the same rear cross-sectional view of FIG. 18, in theunlocked state,

FIGS. 20A and 20B are a side and bottom view, respectively, of the slidedoor of FIG. 18,

FIG. 21 is a front cross-sectional view of the vicinity to the side ofthe tape outlet opening of a magnetic tape cartridge according to thefourth invention of the present application, which shows the slide doorin the locked state,

FIGS. 22A and 22B are cross-sectional views of the main part of theslide door of FIG. 21 in the locked and unlocked states, respectively,

FIG. 23 is a vertical cross-sectional view of the main part of thestructure of the leader pin in a conventional magnetic tape cartridge,

FIG. 24 is a cross-sectional plan view of one part of that shown in FIG.23,

FIG. 25 is a perspective view of the latch spring of FIGS. 23 and 24,

FIG. 26 illustrates a conventional magnetic tape cartridge, in the statein which the flange of the leader pin is brought into abutment with theguide surface of the latch spring when the leader pin is inserted intothe cartridge casing, for purposes of explanation vis-à-vis FIG. 2, and

FIG. 27 is a plan view of the vicinity to the side of the tape outletopening of a conventional magnetic tape cartridge, with the upper halfof the cartridge casing removed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, based on the embodiments illustrated in the drawings andwith reference thereto, the present invention will be explained indetail.

FIG. 1 is a perspective view of an example of an embodiment of themagnetic tape cartridge of the present invention. Magnetic tapecartridge 1 comprises a substantially rectangular and flat cartridgecasing 4 formed of upper half 2 and lower half 3 fastened together byscrews, etc., and a single reel 7 around which is wound a magnetic tape6, contained within cartridge casing 4 for rotation, and a loading-useleader pin 5 to which the tail end of magnetic tape 6 is fixed. On onesidewall (the left sidewall) of cartridge casing 4 (upper and lowerhalves 2 and 3) is formed a tape outlet opening 8, which is opened andclosed by use of a door spring 12 described below that props a slidedoor 20 in the direction of the closing position, and in the vicinity tothe side of tape outlet opening 8, a pair of concave recesses 9 areformed in the upper half 2 and lower half 3, into which leader pin 5 isemplaced and held.

In addition, when magnetic tape cartridge 1 is not being used, magnetictape 6 is in the state in which it is completely wound around reel 7,and leader pin 5 to which the tail end of magnetic tape 6 is fixed isengaged and held in recess 9. Recess 9 is comprises a contiguous guidesurface 10 structured so as to urge leader pin 5 toward tape outletopening 8, and the flanges 5 c of leader pin 5 are guided toward recess9. Further, in order that leader pin 5 is removably held in recess 9, asshown for example in FIG. 26, a latch spring 30 is fitted in thevicinity of recess 9.

Note that, the insertion direction of magnetic tape cartridge 1 into therecord and playback apparatus is the diagonal upper left direction ofFIG. 1, and in this specification, the directions forward and rearcorrespond to aforementioned insertion direction.

FIG. 2 shows an embodiment of the magnetic tape cartridge according tothe first invention of the present application. FIG. 26 corresponds to aview of the state in which guide surface 31 at the free end of latchspring 30 is brought into abutment with leader pin 5 when leader pin 5is inserted into cartridge casing 4.

Leader pin concave emplacement recess 9 comprises inclined guide wallsurfaces 9A and 9B that guide flanges 5 c of leaer pin 5 into the backof recess 9, and a semispherical holding wall surface 9C, which is of adiameter slightly larger than that of flanges 5 c.

In addition, leader pin 5 is basically structured so that the centeraxis S thereof passes through the center of the curvature ofsemi-spherical holding wall surface 9 c in the back of recess 9 along aperpendicular center line L1 of the sidewall of tape outlet opening 8 ofcartridge casing 4 and is inserted into the recess 9.

Latch spring 30 is provided with a pair of leader pin holding portions30 d formed at the end of resilient arms 30 b. Each pin holding portion30 d protrudes in a mound-shape, and a rear inclined pin guide surface31 is formed at the lead end thereof. Guide surface 31 inclines only atan angle α relative to straight line L2, which runs parallel to centerline L1. The incline angle α is set within the range of 30°±5°.Therefore, the angle between guide wall surface 9 a of recess 9 on thelatch spring 30 side and aforementioned straight line L2 is 10°, andangle β between guide surface 31 and guide wall surface 9 a on the latchspring 30 side is 20°±5°.

In this way, by having the incline angle α set within the range of30°±5° in the current embodiment, even for cases in which the path alongwhich leader pin 5 is inserted into cartridge casing 4 is off track, asshown in FIG. 3, wherein leader pin 5 is inserted at an inaccurateorientation to the degree and flange 5 c of leader pin 5 is brought intoabutment with guide wall surface 9A, and moreover even if the positionof guide surface 31 of latch spring 30 is inaccurate, arm 30 b of latchspring 30 is laterally deflected by the pressure of flange 5 c broughtinto abutment with guide surface 31. As shown in FIG. 3, flange 5 creaches pin holding portion 30 d of latch spring 30 and also passes overthe mound of in holding portion 30 d, and as shown in FIG. 4, by theresilient force of pin holding portion 30 d of latch spring 30, flange 5c is pushed into holding wall surface 9 c of recess 9 and held in placethere.

The 30°±5° range of angle α is a value that was arrived at over thecourse of numerous experiments carried out by the developers of thepresent invention, etc. For cases in which there is a large deviancefrom this range, latch spring 30 is not smoothly deflected by only theinsertion operation of leader pin 5, and if the deviation from saidrange is small, the angle at which leader pin 5 is received by guidesurface 31 of latch spring 30 is small, whereby leader pin 5 is not ableto be sufficiently guided; in either case, impediments to the insertionof leader pin 5 are incurred.

Note that in FIGS. 2-4, latch spring 30 is shown as a straight line, andflat form, however, guide surface 31 can be formed as an oval or curvedsurface, in which case, if the angle α the point at which leader pin 5and guide surf ace 31 are brought into abutment is in the range of30°±5° it performs well. That is to say, at whatever position on guidesurface 31 that flange 5 c comes into contact, if the angle at the pointof contact is within aforementioned range, regardless of the position atwhich leader pin 5 is inserted into cartridge casing 5, the pressure onarm 30 b of latch spring 30 accompanying insertion operation of leaderpin 5 causes arm 30 b to be laterally deflected, whereby it is possiblefor leader pin 5 to be inserted into cartridge casing 5.

FIGS. 5-11 show an embodiment of the magnetic cartridge of the secondinvention of the present application. FIG. 5 is a front view of thevicinity to the side of tape outlet opening 8, in which the slide dooris in the open state, FIG. 6 is a plan view of that shown in FIG. 5,with the top half of the cartridge casing removed, and FIGS. 7A and 7Bare cross-sectional views of the fixing portion of FIG. 6 in before andafter states, respectively, of its being heat fused closed.

As shown in FIG. 5, leader pin 5 is comprises a shaft-shaped tape clamp5 a at the center portion thereof, which is provided with a C clampmember 5 e into which the lead end of magnetic tape 6 is inserted andclamped, said tape clamp portion 5 a has connected on either end thereofa thin flange 5 d, and on the outside the two flanges 5 d in the axialdirection thereof are small diameter portions 5 b that are caught by therobot arm of the record and playback apparatus, which are separated by apair of plate-shaped flanges 5 c. Leader pin 5 is formed by shaving ametal rod (stainless steel, etc.), and the length of tape clamp portion5 a corresponds to the width of magnetic tape 6. C clamp member 5 e isformed of synthetic resin and has an axial length corresponding to thelength of tape clamp portion 5 a of leader pin 5, extending across theentire length thereof in the axial direction a C-shaped slit is opened,and is structured so that magnetic tape 6 is inserted laterally from theoutside of tape clamp 5 a and elastically clamped.

Latch spring 50 that removably engages and holds leader pin 5, and inrelation to leader pin 5, is fitted on the side opposite the front sidesurface of respective upper and lower halves 2 and 3, and on the topwall of upper half 2 and the bottom wall of lower half 3 are formedrecess 25 for fitting latch spring 50.

As shown in FIG. 6, latch spring 50 of the current embodiment asubstantially U-shaped (hairpin-shaped) wire spring, provided with aleader pin holding portion 50 a at the free end thereof that is broughtinto abutment with the outer circumference of flange 5 c of leader pin5, a bent portion 50 c that extends from leader pin holding portion 50 ain the direction opposite tape outlet opening 8 and is bent into asubstantially 180° oval shape, and a fitting portion 50 d extending inthe direction toward tape outlet opening 8 from bent portion 50. Leaderpin holding portion 50 a is formed in a mound-shape protruding towardthe leader pin 5 side, when leader pin 5 inserted from tape outletopening 8 and moved so as to be brought into abutment with the inclinedsurface at the lead end thereof, arm 50 b is resiliently warped andleader pin 5 is pressed by the inclined surface on the inner side ofleader pin holding portion 50 a into the emplacement-use recess 9 andheld there.

Bent portion 50 c is engaged with and supported by boss-shapedsupporting member 40, received in recess 25 and the side edge of fittingportion 50 d is fixed by heat fused fixing portion 41. Fixing portion 41before being heat fused, as shown in FIG. 7A, on both sides of insertedfitting portion 50 d stand protrusions 41 a. The lead ends ofprotrusions 41 a are heat fused and, as shown in FIG. 7B, protrusions 41a on both sides have become an integral unit and fitting portion 50 d iswrapped and sealed therein.

In the fitted state of latch spring 50, bent portion 50 c is supportedby supporting member 40 and arm 50 b between leader pin holding portion50 a and bent portion 50 c is resiliently transformable. The distance Sbetween supporting member 40 and fixing portion 41 is equal to ⅓ orgreater of the distance L between supporting member 40 and leader pin 5,that is, distance S is set to S≧(⅓) L.

Note that although latch spring 50 has around cross-section, it can alsobe formed of wire spring having an elliptical or angular cross-section.

According to the current embodiment, between leading pin holding portion50 a at the free end of latch spring 50 an fitting portion 50 d there isprovided a bent portion 50 c, said bent portion 50 d being supported bysupporting member 40 so that arm 50 b is resiliently transformable andby fitting portion 50 d being fixed by upper and lower halves 2 and 3that are fixed by fixing portion 41, the effect that the accuracy of theposition of fixing portion 41 has on the position of leader pin 5 isbasically reduced. Moreover, by setting the distance S betweensupporting member 40 and fixing portion 41 to greater than or equal to ⅓of the distance L between supporting member 40 and leader pin holdingportion 50 a, the amount of leader pin holding portion 50 a of the freeend of latch spring 50 projecting toward receiving-use recess 9 isfixed, the engaging power in relation to leader pin 5 is stabilized, andinsertion and removal of leader pin 5 can be performed with accuracy.

FIG. 8 is a plan view of the main part of an example of a changed typeof that shown in FIG. 6, with the upper half removed for illustrativepurposes. FIGS. 9A and 9B are cross-sectional views of the fixingportion before and after heat fusion has been performed.

The basic construction of upper and lower halves 2 and 3, leader pin 5,etc., and the type of latch spring in FIG. 8 are the same as those inFIG. 6, however, the structure of heat fused fixing portion 42 isdifferent.

That is to say, as shown in FIG. 9A, before being heat fused, saidfixing portion 42 has protrusion 42 a on the sidewall of recess 25, andis in the state in which fitting portion 50 d of the latch spring 50 isinserted between protrusion 42 a and the sidewall. Then, the lead end ofprotrusion 42 is heat fused with the sidewall and, as shown in FIG. 9B,protrusion 42 a wraps around and seals in fitting portion 50 d.

In this case, with latch spring 50 in the fitted state, the distance Sbetween supporting member 40 and fixing portion 42 is equal to ⅓ orgreater of the distance L between supporting member 40 and leader pinholding portion 50 a, that is, distance S is set to S≧(⅓) L. Because theother structures are the same as those in FIG. 6, the parts in commonhave the same reference numbers and explanation thereof is omitted.

FIG. 10 is a plan view of the main part of a magnetic tape cartridge ofthe present invention having yet another different type of latch spring.

In this embodiment, latch spring 51 is a wire spring bent into a crankform, and is provided with leader pin holding portion 51 a on the freeend thereof that is brought into abutment with flange 5 c of leader pin5. Extending from leader pin holding portion 51 a in the directionopposite tape outlet opening 8 is arm 51 b, which is bent at bentportion 51 c and bent again to the opposite side, and extending in thedirection opposite tape outlet opening 8 and running substantiallyparallel to arm 51 b is formed straight-line shaped fitting portion 51d.

Bent portion 51 c of the base end of arm 51 b is engaged with andsupported by boss-shaped supporting member 40, received in recess 25 andthe side edge of fitting portion 50 d is inserted (pressure inserted)and supported between boss-shaped fixing portion 43 formed adjacent tothe wall surface of recess 25 and the wall surface.

In the fitted state of latch spring 51, bent portion 51 c is supportedby supporting member 40 and arm 51 b between leader pin holding portion51 a and bent portion 51 c is resiliently transformable. The distance Sbetween supporting member 40 and fixing portion 43 is equal to ⅓ orgreater of the distance L between supporting member 40 and leader pinholding portion 51 a, that is, distance S is set to S≧(⅓) L.

FIG. 11 is a plan view of the main part of a magnetic tape cartridge ofthe present invention having still yet another different type of latchspring.

In this embodiment, latch spring 52 is a substantially L-shaped wirespring, and is provided with leader pin holding portion 52 a on the freeend thereof that is brought into abutment with flange 5 c of leader pin5. Extending from leader pin holding portion 51 a in the directionopposite tape outlet opening 8 is arm 52 b, which is bent at asubstantially 90° angle, and extending in the direction toward the backof recess 9 is straight-line shaped fitting portion 52 d.

Bent portion 52 c of the base end of arm 52 is engaged with andsupported by boss-shaped supporting member 40, received in recess 25 andthe side edge of fitting portion 50 d is fixed by heat fused fixingportion 41 in the same as in FIGS. 6 and 7.

In the fitted state of latch spring 52, bent portion 52 c is supportedby supporting member 40 and arm 52 b between leader pin holding portion52 a and bent portion 52 c is resiliently transformable. The distance Sbetween supporting member 40 and fixing portion 43 is equal to ⅓ orgreater of the distance L between supporting member 40 and leader pinholding portion 51 a, that is, distance S is set to S≧(⅓) L.

Note that in each of the embodiments described above, leader pin holdingportions 50 a-52 a of latch springs 50-52 are disposed so as to projecttoward recess 9 from the side remote from the side wall of the frontside (upper side of Figure) of upper and lower halves 2 and 3, however,the latch spring can also be disposed on the opposite side from this, onthe front side. In that case, a latch spring formed of wire spring, etc.as separate upper and lower members is used: the bent portion thereofbeing supported by a supporting member; the fitting portion being fixedby a fixing portion; and as described above, the distance S between thesupporting member and the fixing portion is set so as to be equal to ⅓or greater of the distance L between the supporting member and theleader pin holding portion.

Next, FIGS. 12-14 show an embodiment of a magnetic tape cartridgeaccording to the third invention of he present application. FIG. 12 is aperspective view of the vicinity to the side of the tape outlet openingwith the slide door in the closed state. FIG. 13 is a frontcross-sectional view of the vicinity to the side of the tape outletopening with the slide door in the locked state. FIG. 14 is frontcross-sectional view of the vicinity to the side of the tape outletopening in the unlocked state.

As shown in FIG. 1, magnetic tape cartridge 1 comprises a substantiallyand flat cartridge casing 4 formed of upper half 2 and lower half 3fastened together by screws, etc., and a single reel 7 around which iswound a magnetic tape 6, contained within cartridge casing 4 forrotation, and a loading-use leader pin 5 to which the tail end ofmagnetic tape 6 is fixed. On one sidewall (the right sidewall) ofcartridge casing 4 (upper and lower halves 2 and 3) is formed a tapeoutlet opening 8, which is opened and closed by use of a door spring 12(refer to FIG. 13) that props a slide door 20 into the direction of theclosed position, and in the vicinity to the side of tape outlet opening8 is formed a door rail 11 (refer to FIG. 13) in the form of a groove inwhich slide door 20 slides.

In addition, when magnetic tape cartridge 1 is not being used, magnetictape 6 is in the state in which it is completely wound around reel 7,and leader pin 5 to which the tail end of magnetic tape 6 is fixed isengaged ad held in recess 9. Recess 9 is comprises a contiguous guidesurface 10 structured so as to urge leader pin 5 toward tape outletopening 8, and the end portion of leader pin 5 is guided toward recess9. Further, in order that leader pin 5 is removably held in recess 9, asshown for example in FIG. 26, a latch spring 30 is fitted in thevicinity of recess 9.

Tape outlet opening 8 is substantially rectangular, and slides betweenthe open and closed positions along door rail 11 formed on the upper andlower edges of respective upper and lower halves 2 and 3. On the leadend of slide door 20, excepting the upper and lower edges thereof, isformed in the center portion thereof an outward projecting openerportion 21. Further, on the open edge of the front end portion of tapeoutlet opening 8 of cartridge casing 4 a section is cut out thatcorresponds to the width of aforementioned opener portion 21. As shownin FIG. 12, opener portion 21 of slide door 20 is slid into this cut outsection 4 a in the closed state the lead end edge of slide door 20 isbrought into abutment with the upper and lower edges of cut out section4 a and stopped in the closed position, and the front-end surface 21 aof opener portion 21 is exposed at the front side of cartridge casing 4.Therefore, when magnetic tape cartridge 1 is inserted and loaded intothe record and playback apparatus, front-end surface 21 a of openerportion 21 is brought into abutment with the door operating member 18(refer to FIG. 14) of the record and playback apparatus, resistance isapplied to door spring 12 and slide door 20 is opened.

As shown in FIGS. 13 and 14, on the lower face of the front end of slidedoor 20 is formed a downward projecting lock portion, which engages witha concave engaging portion 13 formed on the bottom surface of door rail11 so as to lock slide door 20 in the closed position. Further, theupper portion of front-end surface 21 a of opener portion 21 of the leadend of slide door 20, that is, the surface brought into abutment withaforementioned door operating member 18, is formed as a forwardinclining surface with a predetermined incline angle A (for example0.3°) relative to the base surface perpendicular to door opening andclosing direction D. That is to say, as shown in FIG. 14, in the statewherein front-end surface 21 a is brought into abutment with dooroperating member 18, the force component exerted by inclined front-endsurface 21 a relative to pressure A is improved, in the upper directionin which the lock portion 22 of the lower portion of slide door 20 andthe engaging portion 13 are released, door operating member 18 is ableto smoothly move upward.

Note that extending rearward from the rear end of slide door 20 is a rod23 connected thereto, which has compressedly loaded on the outercircumference thereof a door spring 21 composed of a coil spring thatprops slide door 20 in the direction of the closed position. Inaddition, lock portion 22 is formed so that the amount protrudingtherefrom is less than the gap between the upper and lower edges ofslide door 20 in door rail 11, and lock 22 is released by the amount ofmovement of slide door 20 in the up and down directions within door rail11. In that case, in the state in which slide door 20 is closed as shownin FIG. 13, the propping direction of door spring 12 can be set so thatthe front end of slide door 20 receives downward propping force, wherebythe engaging of lock portion 22 and engaging portion 13 is improved.Further, lock 22 can be formed concave and engaging portion 13 convex.

According to the current embodiment, when in a state in which it is notbeing used, such as storage, etc., slide door 20 is propped toward theclosing position by door spring 12, and with tape outlet opening 8 inthe totally closed position, lock portion 22 is engaged with engagingportion 13 so that slide door 20 is locked and does not open due to theimpact from being dropped, etc. When magnetic tape cartridge is used, asshown in FIG. 14, accompanying loading thereof into a record andplayback apparatus, front-end surface 21 a of opener portion 21 isbrought into abutment with door operating member 18 and slide door 20 ispushed toward the opening position. In accordance with pressure A, frontend surface 21 a, inclined at predetermined angle A, of opener portion21 moves upward so that moves door operating member 18 smoothly upward,lock 22 and engaging portion 13 are unlocked, and it becomes possible toopen slide door 20. In this way, the operating power of door operatingmember 18 is used to unlock the locked state, and there is no need toprovide an exclusive-use unlocking member in the current embodiment.

Next, FIGS. 15-17 show an embodiment of a door lock of a differentconstruction. FIG. 15 is a cross-sectional plan view of the lead end ofthe slide door in the locked state. FIG. 16 is the same cross-sectionalplan view of FIG. 15 in the unlocked state. FIG. 17 is a perspectiveview of the lead end of the slide door of FIG. 15.

Slide door 60 of the current embodiment has at the lead end thereofopener portion 61 that is brought into abutment with door operatingmember 18, and a projecting lock portion 32 formed on the back side ofthe inside of opener portion 61, said lock portion 32 couples withconcave engaging portion 14 formed on the end surface of aforementionedcut out section 4 a of cartridge casing 4 so as to lock slide door 20 inthe locked position. Further, as shown in FIG. 17, a slit groove 63 isformed at each of an upper-end portion and an lower-end portion of thebase of opener portion 61 of slide door 60, so that the base of theopener portion 61 has lowered stiffness enabling resilient transformthereof, and a portion between the loch 62 and the lead end of theopener portion 61 is inclined so as to project forward. Therefore, whenopener portion 61 receives operating force A from door operating member18, as shown in FIG. 16, opener portion 61 faces outward, that is, it istransformed in the direction unlocking lock portion 62 and engagingportion 14.

According to the current embodiment, when the magnetic tape cartridge isnot being used, such as when in storage, etc., in the state in whichslide door 60 totally closes tape outlet opening 8, lock portion 32 ofopener portion 61 is coupled with engaging portion 14 so that slide door20 is locked and does not open due to the impact from being dropped,etc. Then, to open slide door 60, as shown in FIG. 16, door operatingmember 18 is brought into abutment with the front end of opener portion61 and according to pressure A, opener portion 61 is transformed in theoutward direction unlocking engagement between locking portion 62 andengaging portion 14, and it becomes possible to open slide door 60. Inthe current embodiment, the operating power of door operating member 18is used to unlock the locked state, and there is no need to provide anexclusive-use unlocking member.

Next, FIGS. 18-20B show an embodiment of a door lock of yet anotherconstruction. FIG. 18 is rear cross-sectional view of the slide door inthe locked state. FIG. 19 is the same rear cross-sectional view in theunlocked state. FIGS. 20A and 20B are a side and bottom view,respectively, of the lead end of the slide door.

In slide door 70 of the current embodiment, there is a lock mechanismemplaced inside the backside thereof. On the front end of slide door 70is formed opener portion 71 that is brought into abutment with dooroperating member 18, extending from said opener portion 71 in the dooropening and closing direction D in a predetermined width is formed aconcave portion 70 a, and intersecting midway with concave portion 70 ais slide groove 71 b extending in the direction running through dooropening and closing direction D. Rod shaped locking member 72 providedwith engaging groove 72 b, which is inclines relative to opening andclosing direction D of slide door 70, is slideably inserted into groove70 b.

Also, unlocking member 73 is slideably inserted into aforementionedconcave portion 70 a. Unlocking member 73 has on the front end thereof apressure portion exposed to the front end surface of opener portion 71of slide door 70, and inclined portion 73 c connected with the rearportion of slide base 73 b, said inclined portion 73 c couples with theinclined engaging groove 72 b of aforementioned locking member 72, andin accordance with the sliding of unlocking member 73, projecting lockportion 72 a is connected so as to project from and recede into thelower end of sliding door 70.

On the rear portion of unlocking member 73 is compressedly loaded apropping spring 74 that props unlocking member 73 in the forwarddirection. Further, projecting lock portion 72 a is formed on the lowerend of locking member 72, said lock portion 72 a projects from andrecedes into the lower end of slide door 70, and in the projectingstate, engages with concave engaging portion 15 on the bottom surface ofdoor rail 11 of lower half 3 to lock slide door 70 in the closedposition, and if locking member 72 moves in the upward direction, theengagement is separated and unlocked.

Note that, as shown in FIG. 18, the engagement between concave portion70 a and unlocking member 73 is constructed in the form of a beveljoint, and the locking member 72 taken hold of unlocking member 73 fromnotched portion 70 c formed on one portion of concave portion 70 a areinstalled, and afterwards, propping spring 74 is taken hold of. On theone hand, a projecting portion 18 a is provided on the lead edge of dooroperating member 18 and a step portion is formed, and at first,projecting portion 72 a is brought into abutment with the front end ofpressure portion 73 a of unlocking member 73, causing unlocking member73 to withdraw, and by this, locking member 72 is slid upward by thecam-like action of unlocking member 73 and the lock is unlocked.

According to the current embodiment, when the magnetic tape cartridge isnot being used, such as when in storage, etc., when slide door 70 is inthe position in which tape outlet opening 8 is totally closed, unlockingmember 73 is moved in the forward direction by propping spring 74, lockportion 72 a of the lead edge of locking member 72 projects from thelower end of slide door 70 and engages with engaging portion 15 so thatslide door 70 is locked and does not open due to the impact from beingdropped, etc. Then, as shown in FIG. 19, projecting portion 18 a of dooroperating member 18 is brought into abutment with the front end surfaceof pressure portion 73 a of unlocking member 73, and by the withdrawalof unlocking member 73, the action of inclined portion 73 causes lockingmember 72 to move in the upward direction and lock portion 72 a andengaging portion 15 are unlocked, whereby it becomes possible to openslide door 70. In the current embodiment, the operating power of dooroperating member 18 is used to unlock the locked state, and there is noneed to provide an exclusive-use unlocking member.

Next, FIGS. 21, 22A and 22B show an embodiment of a magnetic tapecartridge according to the fourth invention of the current application.FIG. 21 is a front cross-sectional view of the slide door in the lockedstate. FIGS. 22A and 22B are cross-sectional views of the main part ofthe lock in the locked and unlocked states, respectively.

Slide door 80 of the current embodiment is provided at the front endthereof with an opener portion 81 that is brought into abutment withdoor operating member 18 to move slide door 80 in the direction of theopening position, and on the lower portion thereof is formed a downwardprojecting convex lock portion 82, said lock portion 82 couples with thethrough-hole serving as a concave engaging portion on the bottom surfaceof door rail 11 of lower half 3 to lock slide door 80 in the closedposition. Above lock portion 82 of slide door 80 is formed an opening83, and by this, the lower edge of opening 83 is formed as a thin warpedportion 84 that is warpedly transformed toward the inside of opening 83when downward pressure is applied to lock portion 82 so as to permitlock 82 to move in the upward direction. In addition, engaging portion16 of lower half 3 asses through the casing wall and by coming intocontact with exterior lock unlocking member 19 (refer to FIG. 22), lockportion 82 is pushed up and warped portion 84 is warpedly transformedtoward the inside of opening 83, and lock portion 82 is extracted fromengaging portion 16 and the locked state is unlocked.

According to the current embodiment, when the magnetic tape cartridge isnot being used, such as when in storage, etc., in the state in whichslide door 80 is in the position in which tape outlet opening 8 istotally closed, lock portion 82 is coupled with engaging portion 15 sothat slide door 80 is locked and does not open due to the impact frombeing dropped, etc. To open slide door 80, as shown in FIG. 22B, whenlock unlocking member 19 is inserted from the outside of lower half 3into engaging portion 16 and lock portion 82 is pushed up, through lockportion 82, warped portion 84 is transformed and lock portion 82 isuncoupled from engaging portion 16 and the locked state is unlocked. Bythe forward end of opener portion 81 being brought into abutment withdoor operating member 18, slide door 80 is opened. In the currentembodiment, aside from door operating member 18, the record and playbackapparatus is also required to be equipped with lock unlocking member 19.

What is claimed is:
 1. A magnetic tape cartridge comprising: a cartridgecasing; a single reel around which a magnetic tape is wound and which iscontained in the cartridge casing for rotation; a leader pin fixed to alead edge of the magnetic tape; a latch spring provided in the cartridgecasing, the latch spring removably holding an end of the leader pinwithin the cartridge casing, the latch spring being laterallydeflectable by the leader pin when the leader pin is inserted into thecartridge casing, the latch spring provided with a guide surface thatfacilitates insertion of the leader pin into the cartridge casing and aholding portion that holds the leader pin within the cartridge casingafter the leader pin has passed over the guide surface, wherein anincline angle at a point at which the leader pin is brought intoabutment with the guide surface, relative to an insertions direction ofthe leader pin, is set within a range of 30°±5°.
 2. A magnetic tapecartridge according to claim 1, wherein the incline angle is dividedinto two portions by a guide wall surface of the cartridge casing, andwherein an angle of the guide wall surface relative to the insertiondirection of the leader pin is set at 10°, and an angle between theguide surface and the guide wall surface is set within a range of20°±5°.